fix(gnovm): in op_binary, return typed booleans where appropriate (gn…

…olang#3298)

bool8.gno was failing, because the result of the `==` expression is an
untyped boolean, while the first value is a typed boolean. This PR
ensures that if either of the values in a binary expression is typed, we
return a typed bool instead of an untyped bool.

---------

Co-authored-by: ltzmaxwell <[email protected]>

gnovm/pkg/gnolang/preprocess.go

@@ -3574,6 +3574,10 @@ func checkOrConvertType(store Store, last BlockNode, n Node, x *Expr, t Type, au
 						checkOrConvertType(store, last, n, &bx.Left, rt, autoNative)
 						checkOrConvertType(store, last, n, &bx.Right, rt, autoNative)
 					}
+					// this is not a constant expression; the result here should
+					// always be a BoolType. (in this scenario, we may have some
+					// UntypedBoolTypes)
+					t = BoolType
 				default:
 					// do nothing
 				}

gnovm/tests/files/bool8.gno

@@ -0,0 +1,17 @@
+package main
+
+// results from comparisons should not be untyped bools
+
+var a interface{} = true
+
+func main() {
+	buf := "hello="
+	isEqual(a, (buf[len(buf)-1] == '='))
+}
+
+func isEqual(v1, v2 interface{}) {
+	println("v1 == v2", v1 == v2)
+}
+
+// Output:
+// v1 == v2 true